Is it intended that previously scouted enemy structures are not visible on planets you have previously scouted but don't currently have vision on?
At first I thought this may be intended, but then I noticed I can still see the list of previously scouted structures in the ships tab, and if I click on them, they take the camera to their location (even though no model nor icon is shown on the actual game view), so clearly you still have the identity and positional information. So this seems like an odd omission not to draw them.